A pathological pelagic eagle ray (Myliobatiformes: Aetobatidae) tooth plate from the Neogene of Calvert Cliffs, Maryland, U.S.A.

2021 ◽  
Author(s):  
Stephen J. Godfrey ◽  
Michael Scott Verdin ◽  
John Maisey
Keyword(s):  
Tooth Plate

scholarly journals Guianacara dacrya, a new species from the rio Branco and Essequibo River drainages of the Guiana Shield (Perciformes: Cichlidae)

2011 ◽  
Vol 9 (1) ◽  
pp. 87-96 ◽  
Author(s):  
Jessica H Arbour ◽  
Hernán López-Fernández
Keyword(s):  
New Species ◽  
River Basins ◽  
Guiana Shield ◽  
Dorsal Fin ◽  
White Spots ◽  
Tooth Plate ◽  
Northern Brazil ◽  
Pharyngeal Jaw ◽  
River Drainages ◽  
A New Species

A new species of Guianacara is described from tributaries of the Essequibo River and the rio Branco in Guyana and northern Brazil. Guianacara dacrya, new species, can be diagnosed from all congeners by the possession of a unique infraorbital stripe and by the shape of the lateral margin of the lower pharyngeal jaw tooth plate. Guianacara dacrya can be further distinguished from G. geayi, G. owroewefi, G. sphenozona and G. stergiosi by the possession of a thin midlateral bar, from G. cuyunii by the possession of dusky branchiostegal membranes and from G. oelemariensis by the possession of two supraneurals. This species differs from most congeners by the presence of white spots on the spiny portion of the dorsal fin, the placement of the midlateral spot, the presence of filaments on the dorsal, anal and in rare cases the caudal-fin and from at least the Venezuelan species by several morphometric variables. Guianacara dacrya is known from the Essequibo, Takutu and Ireng River basins of Guyana and possibly from the rio Uraricoera in the rio Branco basin in Brazil. A key to the species is provided.

scholarly journals A Lungfish (Sarcopterygii, Dipnomorpha) Tooth Plate from the Lower Devonian of Vietnam and the Onset of Modern Dipnoan Dental Organization

2020 ◽  
Vol 40 (1) ◽  
pp. e1772274
Author(s):  
Jorge Mondéjar-Fernández ◽  
Thomas J. Challands ◽  
H. Nguyên Huu ◽  
P. Ta Hoa ◽  
Gaël Clément ◽  
...  
Keyword(s):  
Lower Devonian ◽  
Tooth Plate

scholarly journals An Investigation on Mechanical Behavior of Tooth-Plate-Glass-Fiber Hybrid Sandwich Beams

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Honglei Xie ◽  
Li Wan ◽  
Bo Wang ◽  
Haiping Pei ◽  
Weiqing Liu ◽  
...  
Keyword(s):  
Glass Fiber ◽  
Failure Modes ◽  
Bending Strength ◽  
Fibrous Composite ◽  
Strain Energy Release ◽  
Metal Plate ◽  
Plate Glass ◽  
Foam Core ◽  
Sandwich Beams ◽  
Tooth Plate

Tooth-plate-glass-fiber hybrid sandwich (TFS) is a type of sandwich composites fabricated by vacuum-assisted resin infusion process, in which glass fiber facesheets reinforced by metal plate are connected to foam core through tooth nails. Bending properties and interlaminar properties of TFS beams with various foam densities were investigated by flexural tests and DCB (double cantilever beam) tests. The test results showed that by increasing the foam core density from 35 kg/m3 to 150 kg/m3, the peak strength of TFS beams significantly increased by 168% to 258% compared with similar sandwich beams with fibrous composite facesheets. With the change of foam density and span length, the main failure modes are core shear and facesheet indentation beneath the loading roller. The interlaminar strain energy release rates of TFS specimens also increased by increasing the density of the foam. In addition, an analytical model was used to predict the ultimate bending strength of TFS beams, which were in good accordance with the experimental results.

The relationships of Uronemus : A Carboniferous dipnoan with highly modified tooth plates

1987 ◽  
Vol 317 (1185) ◽  
pp. 299-327 ◽  
Keyword(s):  
Tissue Type ◽  
Close Relative ◽  
Marginal Tooth ◽  
Thin Sections ◽  
Scanning Electron Microscope Study ◽  
Air Breathing ◽  
Dental Tissues ◽  
Lower Jaw ◽  
Tooth Plate ◽  
Evolutionary Phase

Previous accounts of the dentition of the Carboniferous dipnoan Uronemus have stressed the significance of the scattered small denticles. These, together with the marginal teeth and ridges, have been interpreted as primitive characters of the dipnoan dentition shared with three other genera: the Devonian Uranolophus and Griphognathus and the Carboniferous to Permian Conchopoma . Genera with tooth plates have been considered to be a monophyletic group in which tooth plates are a derived character; Uronemus has been excluded from this group in all previous investigations dealing with the significance of the dentition for determining relationships among dipnoans. The macromorphology of the dentition of Uronemus has been re-examined and correlated with the histology of all the dental tissues. Optical study of thin sections and scanning electron microscope study of the adjacent cut surfaces has shown that the hard, wear-resistant dentine of the teeth and ridges is petrodentine. The arrangement, growth, wear and histology of the dental tissues have been compared with those of denticulated and tooth-plated genera. The arrangement of new teeth relative to the tooth ridge, the pattern of wear along the ridge, and the type of dentine and its growth indicate that the dentition of Uronemus is best interpreted as a tooth plate with one long lingual tooth ridge and reduced lateral tooth rows. Therefore the marginal tooth ridges are not considered to be homologous with those of denticulate dipnoans such as Uranolophus . The presence of petrodentine, a tissue type only found in forms with tooth plates, is consistent with the view that the dentition is derived by modification of a radiate tooth plate. The denticles covering restricted regions of the palate and lower jaw are considered to have been a secondary acquisition. The suggestion that Conchopoma is a close relative of Uronemus is not accepted, and possible new relationships have been proposed. New data on Scaumenacia and Phaneropleuron , two other genera previously compared with Uronemus , are presented. Rhinodipterus , a form with elongate lingual ridges, is also discussed. Phaneropleuron is shown to have radiate tooth plates and not a marginal row of conical teeth as previously described. It is proposed that the tooth plate of Uronemus is derived from a dipterid type of plate. A discussion of some of the other factors involved in determining the relationships of the genus is given. From an examination of the use of the tongue for respiration and feeding by the extant Lepidosiren paradoxa , it is concluded that many features of dipnoan evolution in the tooth-plated lineage result from the adoption of air breathing after an early evolutionary phase of gill respiration, and that Uronemus was adapted for air breathing. The ‘denticulated’ lineage, which included genera such as Uranolophus and Griphognathus , shows none of the skeletal features associated with the presence of a tongue, and presumably did not become air breathing.

scholarly journals TOOTH-PLATE REMOVED FROM THE RIGHT BRONCHUS BY INFERIOR BRONCHOSCOPY

BMJ ◽  
1924 ◽  
Vol 2 (3317) ◽  
pp. 145-140 ◽  
Author(s):  
E. B. Waggett ◽  
E. L. Fyffe
Keyword(s):  
Tooth Plate ◽  
The Right

Australian Triassic lungfish skulls

1994 ◽  
Vol 68 (3) ◽  
pp. 647-654 ◽  
Author(s):  
A. Kemp
Keyword(s):  
New South ◽  
New South Wales ◽  
Three Dimensional ◽  
Lower Triassic ◽  
South Wales ◽  
Tooth Plate ◽  
Dimensional Reconstruction ◽  
First Time ◽  
To Receive ◽  
Australian Lungfish

Skull bones of Gosfordia truncata Woodward, 1891, from the Lower Triassic Hawkesbury Sandstone of New South Wales, Australia, are described for the first time. The skull roofing pattern suggests possible affinities between G. truncata and Paraceratodus germaini (Triassic, southwest Madagascar). A three-dimensional reconstruction of the skull of Ceratodus formosus Wade, 1935, based on the holotype, found in a Lower Triassic deposit at Brookvale in New South Wales, is included. This reconstruction indicates that this species is not closely related either to the recent Australian lungfish, Neoceratodus forsteri, or to the Triassic Ceratodus (Tellerodus) sturii from Nord Alpen in Austria, and it has no close affinities with G. truncata. A new genus, Ariguna, is therefore proposed to receive Ceratodus formosus Wade, 1935. Without associated tooth plate material, G. truncata and A. formosa cannot be defined more precisely.

First Triassic lungfish from the Arabian Peninsula

2010 ◽  
Vol 84 (1) ◽  
pp. 137-140 ◽  
Author(s):  
Benjamin P. Kear ◽  
Thomas H. Rich ◽  
Mohammed A. Ali ◽  
Yahya A. Al-Mufarrih ◽  
Adel H. Matiri ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
North America ◽  
Middle East ◽  
Arabian Peninsula ◽  
Arabian Shield ◽  
Eastern Asia ◽  
Marine Deposits ◽  
Eastern Margin ◽  
Tooth Plate ◽  
Single Tooth

Triassic lungfish (Dipnoi) have been extensively documented from the Gondwanan continental and marine shelf deposits of Africa and Madagascar (Teixeira, 1949; Lehman et al., 1959; Beltan, 1968; Martin, 1979, 1981; Kemp 1996), Australia (Kemp, 1993, 1994, 1997a, 1998), India (Jain et al, 1964; Jain, 1968), and Antarctica (Dziewa, 1980). Numerous records also exist from Laurasian landmasses including Europe (Agassiz, 1838; Schultze, 1981), North America (Case, 1921) and central and eastern Asia (Liu and Yeh, 1957; Vorobyeva, 1967; Martin and Ingavat, 1982). By comparison, nothing is known of contemporary lungfish fossils from the Middle East. Thus, the recent recovery of a single tooth plate representing a new geographic occurrence of the genus Ceratodus Agassiz, 1838 from paralic marine deposits of the Jilh Formation, a latest Anisian to lower Carnian unit that crops out along the eastern margin of the Proterozoic Arabian Shield in central Saudi Arabia (Fig. 1), is significant because it provides the stratigraphically oldest record of dipnoans from the Arabian Peninsula.

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